1. Field of the Invention
The present invention relates to an active matrix display device and a semiconductor device in which elements are arranged in matrix.
2. Description of the Related Art
As an image display device, a liquid crystal display device, an electroluminescence (hereinafter referred to as “EL”) display device, and the like have been previously known. As types of these display devices, there are a passive matrix display device and an active matrix display device. The active matrix display device can perform high-speed operation even when the number of pixels is increased.
As the active matrix display device, a TFT, a capacitor, a wiring, a pixel electrode, and the like are formed over one substrate; because of this, an aperture ratio tends to decrease. Accordingly, an attempt to increase the aperture ratio is done by creating design such as materials, shapes, the number, or arrangement of the TFT, the capacitor, the wiring, the pixel electrode, and the like. For example, a method for decreasing the area of a capacitor by using tantalum oxide, which has a high dielectric constant, as a dielectric of the capacitor is disclosed in Patent Document 1.    Patent Document 1: Japanese Published Patent Application No. H11-312808.